Pulsed corona discharge for improving treatability of coking wastewater.

Coking wastewater (CW) contains toxic and macromolecular substances that inhibit biological treatment. The refractory compounds remaining in biologically treated coking wastewater (BTCW) provide chemical oxygen demand (COD) and color levels that make it unacceptable for reuse or disposal. Gas-phase pulsed corona discharge (PCD) utilizing mostly hydroxyl radicals and ozone as oxidants was applied to both raw coking wastewater (RCW) and BTCW wastewater as a supplemental treatment. The energy efficiency of COD, phenol, thiocyanate and cyanide degradation by PCD was the subject of the research. The cost-effective removal of intermediate oxidation products with addition of lime was also studied. The energy efficiency of oxidation was inversely proportional to the pulse repetition frequency: lower frequency allows more effective utilization of ozone at longer treatment times. Oxidative treatment of RCW showed the removal of phenol and thiocyanate at 800 pulses per second from 611 to 227mg/L and from 348 to 86mg/L, respectively, at 42kWh/m3 delivered energy, with substantial improvement in the BOD5/COD ratio (from 0.14 to 0.43). The COD and color of BTCW were removed by 30% and 93%, respectively, at 20kWh/m3, showing energy efficiency for the PCD treatment exceeding that of conventional ozonation by a factor of 3-4. Application of lime appeared to be an effective supplement to the PCD treatment of RCW, degrading COD by about 28% at an energy input of 28kWh/m3 and the lime dose of 3.0kg/m3. The improvement of RCW treatability is attributed to the degradation of toxic substances and fragmentation of macromolecular compounds.

Rapid determination of anilines in water samples by dispersive liquid-liquid microextraction based on solidification of floating organic drop prior to gas chromatography-mass spectrometry.

A rapid, sensitive and environmentally friendly method for the analysis of 14 anilines in water samples by dispersive liquid-liquid microextraction based on solidification of floating organic drop (DLLME-SFO) prior to gas chromatography-mass spectrometry (GC-MS) was developed and optimized. In the proposed method, cyclohexane was used as the extraction solvent as its toxicity was much lower than that of the solvent usually used in dispersive liquid-liquid microextraction (DLLME). In the optimized conditions, the method exhibited good analytical performance. Based on a signal-to-noise ratio of 3, limits of detection for anilines were in the range of 0.07 to 0.29 µg L(-1), and the linear range was 0.5-200 µg L(-1) with regression coefficients (r(2)) higher than 0.9977. It was efficient for qualitative and quantitative analysis of anilines in water samples. The relative standard deviations varied from 2.9 to 8.6% depending on different compounds indicating good precision. Tap water and river water were selected for evaluating the application to real water samples. The relative recoveries of anilines for the two real samples spiked with 10 µg L(-1) anilines were in the scope of 78.2-114.6% and 77.3-115.6%, respectively.

Enhancement of phenol biodegradation: Metabolic division of labor in co-culture of Stenotrophomonas sp. N5 and Advenella sp. B9.

The aim of this work is to study the synergistic effect of Stenotrophomonas sp. N5 and Advenella sp. B9 co-culture (COC) on enhancement of phenol biodegradation. These two strains utilizing phenol as sole carbon and energy source were isolated from phenol-containing coking wastewater. The results of biodegradation experiment showed the COC of N5 and B9 has stronger capability to degrade phenol than either of mono-culture (MOC). Growth kinetics studies indicated inhibitory effect of phenol on COC was reduced by the interaction of N5 and B9 in COC. The RNA-Seq results demonstrated that phenol biodegradation was enhanced by metabolic division of labor (DOL) in COC based on the expression of key genes for phenol degradation. GO enrichment analysis of differentially expressed genes (DEGs) indicated DEGs between COC and MOC degradation systems are mainly concentrated in the synthesis of cell components, microbial growth and metabolism, and catalytic activity. The expression of 3 transcriptional factors (LysR, Two-component system response regulator, and TetR families) which can regulate degradation of aromatic compounds, was identified beneficial to phenol degradation.

Dechlorination of chlorobenzene in subcritical water with Fe/ZrO2, Ni/ZrO2 and Cu/ZrO2.

To obtain information about dechlorination of organochlorine compounds in subcritical water catalyzed by metals assisted with ZrO(2), dechlorination of chlorobenzene has been investigated in the presence of Fe/ZrO(2), Ni/ZrO(2) and Cu/ZrO(2) catalysts. The dechlorination efficiency was increased with increasing residence time, temperature and pressure. The order of effectiveness of the catalysts was Cu/ZrO(2) < Ni/ZrO(2) < Fe/ZrO(2). The dechlorination of chlorobenze obeyed pseudo-first-order kinetics models. The rate constants in subcritical water were much greater than that in ambient-temperature water; the activation energies were obtained. ZrO(2) in the catalyst had the power to absorb chlorobenzene onto the catalyst surface and promoted the dechlorination ability of the metal. The primary mechanism for dechlorinaton of chlorobenzene involved the reduction of chlorobenzene by reaction with nascent hydrogen. The nascent hydrogen reacted with the chlorobenzene, which adsorbed on the catalyst in non-planar and co-planar form, and formed benzene and chloride ions.

[Performance and Mechanisms of Advanced Nitrogen Removal via FeS-driven Autotrophic Denitrification Coupled with ANAMMOX].

Synergy among members of complex microbial communities in the transformation of elements is a key ecological regulation strategy in nature. Making full use of this phenomenon and achieving functional combinations of different microorganisms may have a significant effect on developing new wastewater treatment processes. In this study, nitrogen-containing pollutants were applied in a static batch experiment. The dosage of FeS, the ratio of NO3--N/NO2--N, and the ratio of ANAMMOX (AN) to autotrophic denitrification (AD) biomass were the controlled reaction conditions. The cooperation mechanism resulting from the metabolic complementation of AN and AD is discussed, and the concept of a (AN+AD)TN 0 nitrogen removal process is proposed. This study showed that the excessive dosage of FeS could ensure the more thorough reaction of AD without significantly affecting the metabolic activity of AN bacteria. A complex microbial community was involved in the competition for metabolic substrates when the proportion of NO2--N in the electron acceptor was increased, resulting in a negative impact on the removal of TN. The increase of AN biomass contributed to the strengthening of the cooperation between AN and AD. When the stoichiometric ratio of NH4+-N to NO3--N was less than 0.85, TN could be completely removed. The results showed that a more effective wastewater treatment process may be established by understanding the interactions between microorganisms, and by manipulating or regulating complex microbial communities. This could achieve the efficient removal of pollutants under low material consumption conditions.

[Evaluation of Advanced Nitrogen Removal from Coking Wastewater Using Sulfide Iron-containing Sludge as a Denitrification Electron Donor].

In general, it is difficult to reach the total nitrogen discharge standard in the effluent after municipal and industrial wastewater treatment. The problems hindering advanced denitrification include an unstable C/N ratio in the influent wastewater, increased hydraulic loading with increasing reflux ratio, reduced reaction kinetics, high energy consumption, and secondary pollution and high sludge yield resulting from addition of organic carbon sources. Therefore, deep denitrification with the advantages of energy savings and easy operation is urgently needed. To address these issues, chemical iron sulfide sludge, collected after the pretreatment of sulfur-containing industrial wastewater, was used as a solid-phase electron donor to perform advanced denitrification using autotrophic denitrifiers. In this study, the secondary biological effluent of coking wastewater was the influent for denitrification and the performance of denitrification, transformation of sulfide and iron in the sludge, and microbial community changes were investigated. The optimal reaction conditions and effect range of the technology for deep denitrification of wastewater were then calculated. When the concentrations of NO3--N and NO2--N in the influent were (74.54±0.57) and (1.11±0.19) mg·L-1, respectively, the corresponding concentrations in the effluent were reduced to (2.78±1.08) and (2.87±0.71) mg·L-1, respectively, with a hydraulic retention time (HRT) of 18 h. The removal rate of TON (NO3--N+NO2--N) was as high as 90.0%, of which the reduction rate of NO3--N and the accumulation rate of NO2--N were 12.06 and 7.74 mmol·(L·d)-1, respectively. This study showed that the use of chemical sulfide iron sludge as an electron donor for deep denitrification is of practical importance, as it could simplify the subsequent treatment of sulfur- and iron-rich chemical sludge, finally reaching the goal of resource utilization.

[Behavior and Degradation of Polycyclic Aromatic Hydrocarbons (PAHs) in Coking Wastewater of A/O2 and A/O/H/O Processes].

Polycyclic aromatic hydrocarbons (PAHs) are typical organic pollutants found in coking wastewater, and their behavior and reduction can be affected by different treatment processes. Based on these considerations, this study investigated the behaviors of PAHs in coking wastewater under A/O2 and A/O/H/O treatment processes, respectively. In order to evaluate variations in PAH removal under two different treatment processes, samples were taken from different treatment units for quantification of PAHs using gas chromatography-mass spectrometry. Results showed that PAHs were barely degraded in anaerobic tanks of either treatment process and accumulated much higher concentrations than in aerobic and hydrolytic tanks. While low molecular weight PAHs (LMW PAHs) in aqueous phase from anaerobic tanks were degraded effectively in aerobic tanks, high molecular weight PAHs (HMW PAHs) mostly accumulated in the sludge phase; these potentially pose a higher environmental risk and therefore need to be treated separately. Moreover, the A/O/H/O process showed higher degradation of PAHs bioavailability and higher removal effectiveness for PAHs with four or more benzene rings than the A/O2 process; this is attributed to the hydrolytic tank's ability to promote hydrolysis of macromolecular organic compounds and therefore improve biodegradability of PAHs. Comprehensive results from the study indicated that the A/O/H/O process is more advantageous for degradation of PAHs than the A/O2 process.

[Characteristic of Benzo[a]pyrene Anaerobic Degradation by Phenol Co-substrate and Microbial Communities from Two Types of Sludge].

Benzo[a]pyrene (BaP) is a typical representative of PAHs in coking wastewater and priority-controlled pollutants in the coking industry; its response characteristics with microorganisms and the methods to promote its degradation are worth studying. On the other hand, because the inoculated sludge for the adjustment and operation of newly-constructed coking wastewater treatment plants comes from municipal sludge or other coking plants, currently, the study of the microbial properties of different sludges', sludge availability, and the conditions that influence these properties are lacking. On account of the above perspectives, an experiment to study and compare the durability of municipal sludge and coking sludge, and their ability to degrade BaP was carried out. An anaerobic reactor was selected for the experiment and anaerobic-activated sludges were collected from a coking wastewater processing unit and a municipal wastewater plant. Then, 10 mg·L-1 of BaP alone and BaP with phenol as a co-metabolic carbon source was added to the coking and municipal sludge samples, respectively, for comparison experiments to study the microbial degradation of BaP and its dynamics. Moreover, high-throughput sequencing technology was also used to analyze the changes in the microbial community structure before and after the degradation experiment. The results showed that:① Both sludges were capable of degrading BaP, but municipal sludge showed a higher degradation efficiency than coking sludge; ② Adding phenol as co-substrate promoted the biodegradation of BaP in both sludges. When BaP was the sole carbon source, the half-life of BaP in the two sludges was 155.41 d and 116.3 d respectively. After the addition of phenol, the half-life was reduced to 81.25 d and 38.44 d, respectively; ③ According to the analysis of the microbial community structure, the community composition in both sludges changed markedly. Moreover, the microbial community in the municipal sludge showed a more evident change than that of the coking sludge. In the coking sludge, the dominant bacteria community changed a little after acclimation, most of the observed bacteria were previously reported common PAH-degrading strains. In contrast, the dominant bacteria community in the municipal sludge varied greatly after acclimation, and the most abundant bacteria were not common PAH-degrading strains. In addition, some frequently reported PAHs-degrading bacteria such as Bacillus sp., Pseudomonas, Achromobacter, and Sphingomonas sp., were identified in both the sludges and were present in high abundance. The results indicated that municipal sludge utilized BaP more actively than coking sludge; this phenomenon can be explained by the fact that municipal sludge contained a higher diversity of microbes that were involved in the degradation of BaP. Furthermore, the presence of phenol promoted the degradation of PAHs like BaP. Therefore, we proposed that the PAHs in coking sludge discharge might be reduced by the addition phenol and municipal wastewater.

Preparation, characterization and photocatalytic activities of boron- and cerium-codoped TiO2.

Boron- and cerium-codoped TiO2 photocatalysts were synthesized using modified sol-gel reaction process and characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), particle size distribution (PSD), diffuse reflectance spectra (DRS), and Brunauer-Emmett-Teller (BET). The photocatalytic activities were evaluated by monitoring the degradation of dye Acid Red B (ARB). The results showed that the prepared photocatalysts were mixed oxides mainly consisting of titania, ceria, and boron oxide. The structure of TiO2 could be transformed from amorphous to anatase and then to rutile by increasing calcination temperature; the transformation being accompanied by the growth of particle size without any obvious change in phase structure of CeO2. The XPS of B(1.6)Ce(1.0)-TiO2 prepared at 500 degrees C showed that a few boron atoms were incorporated into titania and ceria lattice, whereas others existed as B2O3. Cerium ions existed in two states, Ce3+ and Ce4+, and the atomic ratio of Ce3+/Ce4+ was 1.86. When boron and cerium were doped, the UV-Vis adsorption band wavelength showed an obvious shift toward the visible range (< or =526 nm). As the atomic ratio of Ce/Ti increased to 1.0, the absorbance edge wavelength increased to 481 nm. The absorbance edge wavelength decreased for higher cerium doping levels (Ce/Ti = 2.0). The particles size ranged from 122 to 255 nm with a domain at 168 nm (39.4%). The degradation of ARB dye indicated that the photocatalytic activities of boron- and cerium-codoped TiO2 were much higher than those of P25 (a standard TiO2 powder). The activities increased as the boron doping increased, whereas decreased when the Ce/Ti atomic ratio was greater than 0.5. The optimum atomic ratio of B/Ti and Ce/Ti was 1.6 and 0.5, respectively.

Characteristics of high-sulfate wastewater treatment by two-phase anaerobic digestion process with Jet-loop anaerobic fluidized bed.

A new anaerobic reactor, Jet-loop anaerobic fluidized bed (JLAFB), was designed for treating high-sulfate wastewater. The treatment characteristics, including the effect of influent COD/SO4(2-) ratio and alkalinity and sulfide inhibition in reactors, were discussed for a JLAFB and a general anaerobic fluidized bed (AFB) reactor used as sulfate-reducing phase and methane-producing phase, respectively, in two-phase anaerobic digestion process. The formation of granules in the two reactors was also examined. The results indicated that COD and sulfate removal had different demand of influent COD/SO4(2-) ratios. When total COD removal was up to 85%, the ratio was only required up to 1.2, whereas, total sulfate removal up to 95% required it exceeding 3.0. The alkalinity in the two reactors increased linearly with the growth of influent alkalinity. Moreover, the change of influent alkalinity had no significant effect on pH and volatile fatty acids (VFA) in the two reactors. Influent alkalinity kept at 400-500 mg/L could meet the requirement of the treating process. The JLAFB reactor had great advantage in avoiding sulfide and free-H2S accumulation and toxicity inhibition on microorganisms. When sulfate loading rate was up to 8.1 kg/(m3 x d), the sulfide and free-H2S concentrations in JLAFB reactor were 58.6 and 49.7 mg/L, respectively. Furthermore, the granules, with offwhite color, ellipse shape and diameters of 1.0-3.0 mm, could be developed in JLAFB reactor. In granules, different groups of bacteria were distributed in different layers, and some inorganic metal compounds such as Fe, Ca, Mg etc. were found.

Hydrogen generation from polyvinyl alcohol-contaminated wastewater by a process of supercritical water gasification.

Gasification of polyvinyl alcohol (PVA)-contaminated wastewater in supercritical water (SCW) was investigated in a continuous flow reactor at 723-873 K, 20-36 MPa and residence time of 20-60 s. The gas and liquid products were analyzed by GC/TCD, and TOC analyzer. The main gas products were H2, CH4, CO and CO2. Pressure change had no significant influence on gasification efficiency. Higher temperature and longer residence time enhanced gasification efficiency, and lower temperature favored the production of H2. The effects of KOH catalyst on gas product composition were studied, and gasification efficiency were analyzed. The TOC removal efficiency (R(TOC), carbon gasification ratio (R(CG)) and hydrogen gasification ratio (R(HG)) were up to 96.00%, 95.92% and 126.40% at 873 K and 60 s, respectively, which suggests PVA can be completely gasified in SCW. The results indicate supercritical water gasification for hydrogen generation is a promising process for the treatment of PVA wastewater.

[Aerobic Degradation and Microbial Community Succession of Coking Wastewater with Municipal Sludge].

Coking wastewater is a typical industrial wastewater with high toxicity. Its treatment with biological processes is often challenging because it contains constituents inhibiting microbial activity. To study the inhibitory effect and possible acclimation of microbes in coking wastewater treatment, municipal sludge was inoculated into coking wastewater. Time-dependent concentrations of COD, phenol, ammonia nitrogen, and thiocyanide in coking wastewater were analyzed. The microbial community structure was investigated by the Illumina high-throughput sequencing technology during inoculation. The results showed that COD began to decrease after 16 h and 97.1% of phenol disappeared after 40 h. Thiocyanide began to degrade at 72 h and was undetectable after 96 h. Accordingly, the concentration of ammonia increased as the thiocyanide concentrations decreased. High-throughput pyrosequencing analysis showed that the microbial community structure and species richness varied at different culture stages. In the stage of phenol degradation, the abundance of Acinetobacter and Pseudomonas increased rapidly; the species richness was 13.04% of the community at 48 h. In the stage of thiocyanate degradation, Sphingobacterium,Brevundimonas,Lysobacter, and Chryseobacterium were the dominant bacteria and were 16.13% of the community at 96 h. At 144 h, Fluviicola,Stenotrophomonas, and Thiobacillus became the dominant species and were 22.45% of the community abundance. The results showed that municipal sludge can rapidly overcome the toxicity of coking wastewater because the pollutants are degraded rapidly. The microbial community structure changed as wastewater components were degraded. Environmental factors and the competition among bacteria played a key role in microbial community succession.

Supercritical gasification for the treatment of o-cresol wastewater.

The supercritical water gasification of phenolic wastewater without oxidant was performed to degrade pollutants and produce hydrogen-enriched gases. The simulated o-cresol wastewater was gasified at 440-650 degrees C and 27.6 MPa in a continuous Inconel 625 reactor with the residence time of 0.42-1.25 min. The influence of the reaction temperature, residence time, pressure, catalyst, oxidant and the pollutant concentration on the gasification efficiency was investigated. Higher temperature and longer residence time enhanced the o-cresol gasification. The TOC removal rate and hydrogen gasification rate were 90.6% and 194.6%, respectively, at the temperature of 650 degrees C and the residence time of 0.83 min. The product gas was mainly composed of H2, CO2, CH4 and CO, among which the total molar percentage of H2 and CH4 was higher than 50%. The gasification efficiency decreased with the pollutant concentration increasing. Both the catalyst and oxidant could accelerate the hydrocarbon gasification at a lower reaction temperature, in which the catalyst promoted H2 production and the oxidant enhanced CO2 generation. The intermediates of liquid effluents were analyzed and phenol was found to be the main composition. The results indicate that the supercritical gasification is a promising way for the treatment of hazardous organic wastewater.

[Risk Assessment of Trihalomethane Production Using the Beijiang River and the Pearl River, Guangzhou as Drinking Water Sources].

In order to investigate the risk of trihalomethane formation potential (THMFP) in finished waters as drinking water sources, 70 samples, 114 samples, and 70 samples were collected in November 2013, April 2014 and July 2014, respectively from different locations in the Beijiang River and the Pearl River. After filtration by 0.45 µm filter membrane, a total of 254 samples were chlorinated using Uniform Formation Condition (UFC) method for determining their THM Formation Potential (THMFP). The cancer risk and non-cancer risk of THMs were estimated using USEPA risk assessment model while dominant factors for total risk potential were estimated using sensitivity analysis. Among four THM species, chloroform( CF) was the highest ranging from 101.92-2 590.85 µg x L(-1), followed by bromodichloromethane (BDCM), dibromochloromethane (DBCM) and bromoform (BF). Chloroform, the major THMs speciation, accounted for 96.17% of total THMs. Non-cancer and cancer risk from ingesting THMs was estimated. The result indicated that non-cancer risk of THMs level ranged from 2.03 x 10(-7) to 1.00 x 10(-5) and was not more than 1.0 x 10(-5), the minimum or negligible non-cancer risk level defined by the USEPA. The average cancer risk of THMs was 2.91 x 10(-4) for male and 3.30 x 10(-4) for female in the two rivers, respectively, exceeding the minimum or negligible risk level defined by the USEPA (1. 0 x 10 ~6). The difference of cancer risk between the two rivers was that BDCM ranging from 2.50 x 10(-5) to 6.37 x 10(-4) was approximately twice that of CF in Beijing River. BDCM played an important role in the total risk in the Beijiang River while CF played an important role in the total risk in the Pearl River, Guangzhou. Sensitivity analysis showed that CF played an important role in the estimation of total risk potential, and that the direct utilization of water sources from Beijiang River and the Pearl River Guangzhou is dangerous, thus pretreatment is necessary before chlorination.

Sequential dynamic artificial neural network modeling of a full-scale coking wastewater treatment plant with fluidized bed reactors.

This study proposed a sequential modeling approach using an artificial neural network (ANN) to develop four independent models which were able to predict biotreatment effluent variables of a full-scale coking wastewater treatment plant (CWWTP). Suitable structure and transfer function of ANN were optimized by genetic algorithm. The sequential approach, which included two parts, an influent estimator and an effluent predictor, was used to develop dynamic models. The former parts of models estimated the variations of influent COD, volatile phenol, cyanide, and NH4 (+)-N. The later parts of models predicted effluent COD, volatile phenol, cyanide, and NH4 (+)-N using the estimated values and other parameters. The performance of these models was evaluated by statistical parameters (such as coefficient of determination (R (2) ), etc.). Obtained results indicated that the estimator developed dynamic models for influent COD (R (2) = 0.871), volatile phenol (R (2) = 0.904), cyanide (R (2) = 0.846), and NH4 (+)-N (R (2) = 0.777), while the predictor developed feasible models for effluent COD (R (2) = 0.852) and cyanide (R (2) = 0.844), with slightly worse models for effluent volatile phenol (R (2) = 0.752) and NH4 (+)-N (R (2) = 0.764). Thus, the proposed modeling processes can be used as a tool for the prediction of CWWTP performance.

Increasing the sensitivity of headspace analysis of low volatility solutes through water removal by hydrate formation.

This paper reports on the development of a new headspace analytical technique that is based on water removal by hydrate formation (WRHF). By adding anhydrous salt, the liquid water in an aqueous sample will be removed leaving behind volatile analytes that are fully vaporized at temperatures well below their boiling points. With WRHF, the amount of sample in the headspace can be significantly increased, thereby dramatically improving the detection sensitivity. The technique reduces the risk of possible column damage in gas chromatography (GC) systems. The technique was applied to the determination of phenol at different stages of a coking wastewater treatment plant. The results showed that up to mL-levels of sample solution can be used in WRHF HS-GC analysis when 5g of CaCl2 were used as the anhydrous salt. The detection sensitivity for phenol content was 500 times greater than that in earlier HS-GC work that did not incorporate hydrate formation. The proposed WRHF headspace analysis technique is simple and practical, making it a useful tool for quantifying low concentrations of volatile analytes in aqueous samples.

Principal component analysis to assess the efficiency and mechanism for enhanced coagulation of natural algae-laden water using a novel dual coagulant system.

A novel dual coagulant system of polyaluminum chloride sulfate (PACS) and polydiallyldimethylammonium chloride (PDADMAC) was used to treat natural algae-laden water from Meiliang Gulf, Lake Taihu. PACS (Aln(OH)mCl3n-m-2k(SO4)k) has a mass ratio of 10 %, a SO4 (2-)/Al3 (+) mole ratio of 0.0664, and an OH/Al mole ratio of 2. The PDADMAC ([C8H16NCl]m) has a MW which ranges from 5 × 10(5) to 20 × 10(5) Da. The variations of contaminants in water samples during treatments were estimated in the form of principal component analysis (PCA) factor scores and conventional variables (turbidity, DOC, etc.). Parallel factor analysis determined four chromophoric dissolved organic matters (CDOM) components, and PCA identified four integrated principle factors. PCA factor 1 had significant correlations with chlorophyll-a (r=0.718), protein-like CDOM C1 (0.689), and C2 (0.756). Factor 2 correlated with UV254 (0.672), humic-like CDOM component C3 (0.716), and C4 (0.758). Factors 3 and 4 had correlations with NH3-N (0.748) and T-P (0.769), respectively. The variations of PCA factors scores revealed that PACS contributed less aluminum dissolution than PAC to obtain equivalent removal efficiency of contaminants. This might be due to the high cationic charge and pre-hydrolyzation of PACS. Compared with PACS coagulation (20 mg L(-1)), the removal of PCA factors 1, 2, and 4 increased 45, 33, and 12 %, respectively, in combined PACS-PDADMAC treatment (0.8 mg L(-1) +20 mg L(-1)). Since PAC contained more Al (0.053 g/1 g) than PACS (0.028 g/1 g), the results indicated that PACS contributed less Al dissolution into the water to obtain equivalent removal efficiency.

Novel insights into anoxic/aerobic(1)/aerobic(2) biological fluidized-bed system for coke wastewater treatment by fluorescence excitation-emission matrix spectra coupled with parallel factor analysis.

Fluorescence spectroscopy coupled with parallel factor analysis (PARAFAC) was applied to investigate the contaminant removal efficiency and fluorescent characteristic variations in a full scale coke wastewater (CWW) treatment plant with a novel anoxic/aerobic(1)/aerobic(2) (A/O(1)/O(2)) process, which combined with internal-loop fluidized-bed reactor. Routine monitoring results indicated that primary contaminants in CWW, such as phenols and free cyanide, were removed efficiently in A/O(1)/O(2) process (removal efficiency reached 99% and 95%, respectively). Three-dimensional excitation-emission matrix fluorescence spectroscopy and PARAFAC identified three fluorescent components, including two humic-like fluorescence components (C1 and C3) and one protein-like component (C2). Principal component analysis revealed that C1 and C2 correlated with COD (correlation coefficient (r)=0.782, p<0.01 and r=0.921, p<0.01), respectively) and phenols (r=0.796, p<0.01 and r=0.914, p<0.01, respectively), suggesting that C1 and C2 might be associated with the predominating aromatic contaminants in CWW. C3 correlated with mixed liquor suspended solids (r=0.863, p<0.01) in fluidized-bed reactors, suggesting that it might represent the biological dissolved organic matter. In A/O(1)/O(2) process, the fluorescence intensities of C1 and C2 consecutively decreased, indicating the degradation of aromatic contaminants. Correspondingly, the fluorescence intensity of C3 increased in aerobic(1) stage, suggesting an increase of biological dissolved organic matter.

[Preparation of PVA-SA-PHB-AC composite carrier and m-cresol biodegradation by immobilized Lysinibacillus cresolivorans].

Due to the effects of outer environment and concentration limit on the biodegradation of m-cresol, a carrier with adsorption ability was synthesized. A PVA-SA-PHB-AC composite membrane was prepared by adding SA, PHB and AC into PVA immobilization carrier using the combination of freezing-thawing and boric acid methods. A highly-effective m-cresol-degrading strain Lysinibacillus cresolivorans was entrapped in it and the effects of structural properties such as micro-structure, stability and diffusion coefficient on m-cresol biodegradation were investigated. The results showed that PVA-SA-PHB-AC composite membrane had uniform pore opening, of which the average pore size, specific surface area, m-cresol adsorption capacity and diffusion coefficient was 33.68 nm, 15.30 m2 x g(-1), 3.86 mg x g(-1) and 5.62 x 10(-8) m2 x min(-1), respectively. It could be reused for more than two months, m-Cresol removal by immobilized L. cresolivorans was the coupling of adsorption and biodegradation, and the removal rate was jointly determined by mass-transfer rate and biodegradation rate. When the initial concentration of m-cresol was lower than 350 mg x L(-1), the mass-transfer rate of PVA-SA-PHB-AC was smaller than the biodegradation rate. The m-cresol removal rate depended on the mass-transfer rate, when the concentration was higher than 380 mg x L(-1), it was determined by the biodegradation rate. The addition of adsorbent could decrease the mass transfer coefficient in the carrier, while the higher concentration of substrate could be tolerated and the efficient biodegradation could be achieved in a wider range of concentrations. The biodegradation of m-cresol by immobilized microorganism showed that the modified carrier increased the reaction kinetics in a range of initial concentrations.

Principal component analysis to assess the composition and fate of impurities in a large river-embedded reservoir: Qingcaosha Reservoir.

Qingcaosha Reservoir (QR) is the largest river-embedded reservoir in east China, which receives its source water from the Yangtze River (YR). The temporal and spatial variations in dissolved organic matter (DOM), chromophoric DOM (CDOM), nitrogen, phosphorus and phytoplankton biomass were investigated from June to September in 2012 and were integrated by principal component analysis (PCA). Three PCA factors were identified: (1) phytoplankton related factor 1, (2) total DOM related factor 2, and (3) eutrophication related factor 3. Factor 1 was a lake-type parameter which correlated with chlorophyll-a and protein-like CDOM (r = 0.793 and r = 0.831, respectively). Factor 2 was a river-type parameter which correlated with total DOC and humic-like CDOM (r = 0.668 and r = 0.726, respectively). Factor 3 correlated with total nitrogen and phosphorus (r = 0.864 and r = 0.621, respectively). The low flow speed, self-sedimentation and nutrient accumulation in QR resulted in increases in PCA factor 1 scores (phytoplankton biomass and derived CDOM) in the spatial scale, indicating a change of river-type water (YR) to lake-type water (QR). In summer, the water temperature variation induced a growth-bloom-decay process of phytoplankton combined with the increase of PCA factor 2 (humic-like CDOM) in the QR, which was absent in the YR.